Photovoltaic power generation is a clean method of generating electric power using inexhaustible light energy without discharging toxic substances. A solar cell is used for the photovoltaic power generation, which is a photoelectric converter that generates electric power by converting light energy from the sun into electric energy.
Conventionally, an electrode on the back of a light receiving surface of a generally produced solar cell is formed by screen-printing silver paste and aluminum paste on the back surface of a silicon substrate, then drying and firing the pastes. The aluminum formed substantially all over the back surface of the silicon substrate serves as a positive electrode. However, in the process of producing a solar cell module, a lead tab for extracting electric power cannot be soldered directly to the aluminum electrode formed of aluminum. Therefore, a silver electrode is formed, as an electrode for extracting electric power, in such a manner as to partially overlap the aluminum electrode on the back surface of the silicon substrate (see Patent Documents 1 and 2).    Patent Document 1: Japanese Patent Publication No. 2003-273378    Patent Document 2: Japanese Patent Publication No. HEI10-335267